新烟碱类杀虫剂哌虫啶降解菌P4-7的筛选、鉴定及其降解特性的研究

Isolation,Identification and Degradation Characteristics of a Novel cis-Nitromethylene Neonicotinoid Insecticide PaichongdingDegrading Strain P4-7

采用富集培养的方法,从常州南郊农田土壤中筛选出8株以哌虫啶(Paichongding,IPP)为唯一生长碳源和能源的菌株,选择生长速度快和降解率较高的菌株P4-7进一步研究,据18S rDNA序列将其鉴定曲霉属(Aspergillus sp.)。通过单因素试验和初步优化,菌株4-7在20 d对50 mg/L哌虫啶的降解率可达30%,该菌株降解哌虫啶的最适初始p H为7.0、最适接种量为5%。菌株Aspergillus sp.P4-7降解IPP的过程中,检测到2种中间代谢产物M1和M2,经高分辩LC-MS/MS鉴定为C14H17Cl N4O3(M1)、C14H14Cl N3O(M2),实验结果表明,IPP的丙氧基水解成羟其,形成中间产物M1,M1进一步脱硝基,羟基同时氧化形成M2。

Paichongding （IPP） is a novel nitromethylene neonicotinoid recently developed in China. Eight strains which can utilize IPP as sole carbon and energy source were isolated from the field in south of Chan- gzhou, Jiangsu province. The strain P4-7 with higher rate of degrading IPP was selected for further study. Based on 18S rDNA sequence, the strain was identified as Aspergillus sp.. Under the condition of 50 mg/ L of IPP, pH 7.0 and 5 % of inoculum, the degradation rate of IPP within 20 days reached 30 % by the strain P4-7. Two main metabolites （M1 and M2） were detected during IPP degradation process. Based on LC-MS/MS analysis, they were identified as C14 H17 C1N4O3 （M1） and C14 H14 C1N3O （M2）. According to their appearance dynamics, the biodegradation pathway of IPP by P4-7 was proposed. The propyl group of IPP was initially de-esterified and hydrolyzed to form M1, then M1 was transformed into M2 through re- duction of nitro group on M1 and the hydroxyl oxidization.